1. Field of the Invention
The present invention relates to a distributor amplifier, especially to a distributor amplifier having a noise blocking circuit including a comparator and a switch circuit for suppressing and preventing upstream RF noise from entering a cable TV system via a cable.
2. Description of the Related Art
At present, a cable TV system generally provide a cable modem or a set top box for each client to download videos (at a frequency range of 54 MHZ-1000 MHZ), or upload data (at a frequency range of 5 MHZ-42 MHZ) to a host of the cable TV system.
Therefore, a coaxial cable can carry videos having a band of 54 MHz-1000 MHz and upstream RF data having a bandwidth of 5 MHz-42 MHz simultaneously. However, when a user uploads data, noise caused by a hair-drier or a vacuum cleaner, or resulted from other noise sources may accompany the data to enter a cable—for example but not limited to a coaxial cable, to degrade the data transmission.
Some prior art taps or distributors or house amplifiers use an EMI core to tackle noise. However, the effect is not satisfactory because the EMI core can only slightly suppress noise but not prevent noise from entering a cable.
In view of the foregoing problem of the prior art taps, distributors, or house amplifiers, the present invention proposes a distributor amplifier having a noise blocking circuit as a solution.